Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	$ 76,636	$ 71,769
Other comprehensive income (loss)	(44)	389
Balance at end of period	74,150	71,580
AOCI Including Portion Attributable to Noncontrolling Interest
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(297)	(1,264)
Balance at end of period	(341)	(875)
Net unrealized investment losses
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(429)	(1,519)
Other comprehensive income (loss) before reclassifications, net of tax	(156)	339
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	48	131
Other comprehensive income (loss)	(108)	470
Balance at end of period	(537)	(1,049)
Other comprehensive income (loss) before reclassifications, pre-tax	(162)	340
Amounts reclassified from accumulated other comprehensive income (loss), pre-tax	54	131
Change in discount rate on long-duration insurance reserves
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	152	219
Other comprehensive income (loss) before reclassifications, net of tax	68	(74)
Other comprehensive income (loss)	68	(74)
Balance at end of period	220	145
Other comprehensive income (loss) before reclassifications, pre-tax	88	(101)
Foreign currency translation adjustments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	0	0
Other comprehensive income (loss) before reclassifications, net of tax	0	(1)
Other comprehensive income (loss)	0	(1)
Balance at end of period	0	(1)
Net cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	244	239
Other comprehensive income (loss) before reclassifications, net of tax	0	(4)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(4)	(2)
Other comprehensive income (loss)	(4)	(6)
Balance at end of period	240	233
Other comprehensive income (loss) before reclassifications, pre-tax	0	(5)
Amounts reclassified from accumulated other comprehensive income (loss), pre-tax	(6)	(3)
Gains expected to be reclassified	21
Pension and other postretirement benefits
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(264)	(203)
Other comprehensive income (loss)	0	0
Balance at end of period	$ (264)	$ (203)